For me the most important feature I wish I have with 4K builds is card spanning. It's so distracting that we had this feature before. Because the mind blowing 45/48 FHD mode is only 6-7 sec on my camera!!! Ironically, this is just a "coding task" no need to investigate something new. I even tried several times to do this myself, but, despite of vast amount of code analysis background, this task is overkill for me: not enough of C knowledge and details about underlying hardware and OS functionality. Mlv_rec and mlv_lite modules are significantly different regarded how data record is implemented and no possible to just copy code from one to another. I understand, that for main developers this is just boring job, they spend time discovering something new. Anyone with decent C skills and MKIII camera???